Cenozoic Era: Neogene

Himalayas Mountains-

collision begins about in Oligocene and continues today.

Gulf Coast of US

continued expansion of coastal deposits into Gulf of Mexico

Glacial Isostacy

depression of the crust by ice

Continental glaciers because of the weight or the mass of the ice onto the continent depresses

the crust downward

flora and fauna are...

the same general forms as today (although some interesting forms evolved and went extinct)

Glacial Lake Missoula in Montana

was a large proglacial lake in Montana. Abrupt periodical draining of lake by failed ice dams caused massive flooding to the west across Oregon and Washington states. Last flood was 18,000 to 20,000 years before present

Erosional processes working on the topography can show this rebound certain features such as

wave-cut terraces and shorelines. Can be seen in multiple shorelines around the Great Lakes and Hudson Bay area.

Glaciers retreat during warmer interglacial periods

Soil development

Terrestrial Environments: Fauna-

Terrestrial fauna becomes more modern. -Burrowers (rodents) increase in diversity as do songbirds and small reptiles such as snakes. -Modernization of forms which evolved in the Paleogene (Figure 18.7), cat, dog, deer, cattle, antelope, sheep, goats giraffe, pig, and elephants families to name a few. -Evolution of grazers tied to evolution of grasses.

-Volcanic Eruptions-

increased output of ash and gases in atmosphere

Tethys Ocean-

is destroyed with the collision the African plate and smaller associated sub- plates with European plate and the Indian plate with the Asia plate. -Forming, the Alps and Himalayan mountains respectively. -In the Late Miocene the Mediterranean Ocean was blocked off periodically from the flow of water from the Atlantic. -This resulted in its reduction by evaporation and the vast accumulation of salts in the basin.

After the ice melts and this mass is removed the crust rebounds(uplifts) over time this is call

isostatic rebound

Life: Marine Aquatic Environments: Vertebrates-

major expansion in whale species (both carnivorous (toothed) and baleen (zooplankton feeding) whales and dolphins).

1. Changes in co2 in earths atmosphere-

Decrease in co2 would lead to global cooling

Major North America Paleogeographic / Tectonically Related Events:

-Atlantic coast -gulf coast of us -cordilleran region -western us

Climate change:

-Early Miocene time there is a general cooling and drying of global climate. -Antarctica is positioned over southern, polar regions. -Antarctica under goes cooling as circumpolar current forms after Australia move off to north; expansion of ice caps begins during this time. -Sea-level drops globally. (Miocene Glaciation)

Terrestrial Environments: Flora-

-Overall cooling in Miocene reduces global rainfall, general drying of many continental regions; grasslands expanded. -Compositae, family of plants that contain composite flowers (daisy-like flower and lettuces) evolves. -Plants are very climate dependent; tendency for dryer conditions to favor grassland and wetter ones woodlands.

Atlantic Coast

-Slight periods of uplift and erosion related to isostatic adjustments. -Eroded sediment accumulates in down warped coastal embayments (basins). -These embayments are also sites for important Miocene fossil accumulations.

3. Short-term climate changes-

-Solar output -Volcanic Eruptions

Major Global Paleogeographic Events (Outside North America):

-Tethys ocean -Alpine Orogeny -Himalayas Mts. -Antartica

Changes in the Late Neogene Climate leading into the Quaternary Climate:

-Warming in the Pliocene (5 mybp), sea-level rises, global climate become more equable (subtropical zone moves northward into New England). -Cooling begins again at 3.2 mybp (late Pliocene); the modern Ice Age begins. Be able to list some these points of evidence.

Cordilleran Region: Development of Basin and Range Province-

-begins to form in the Miocene with uplift in the western US (between Sierra Nevada Mountains in California and West Texas). It continued into the Pleistocene.

Western us: San Andres Fault-

-forms in the Miocene with the intersection of a MOR with the subduction zone off the coast of California (you can't subduct a MOR). -On the west-side of MOR the large Pacific plate split into the Juan de Fuca plate to the north of the San Andres fault and the Farallon plate to the south. -As the MOR continues to intersect the subduction zone and seal up the San Andres fault grows in length.

Western us: Cascade Range-

-in pacific northwest -forms because of the subduction of the Juan de Fuca plate under North America.

Western us: Columbia River Basalt From-

-it erupts from fissures as area passes over a mantle plume that forms a Hot Spot under that region (western Oregon, Washington, and eastern Idaho) at 13 to 16 mybp. -Today that hot spot is under Yellowstone National Park in Wyoming.

Cordilleran Region: Development of the Colorado Plateau-

-uplift of the Colorado Plateau (Four-Corner Region of the US) begins in the Miocene. -Much of the Grand Canyon was down cut in a period of rapid uplift from 10 to 8 mybp.

Causes for Quaternary Climate Change:

1. Changes in CO2 in earths atmosphere 2. Milankovitch Theory 3. Short-term climate changes

Neogene Period (Late Tertiary) time period?

23-0 mybp

Antarctica separates from ...

Australia and under goes cooling as circumpolar current forms after Australia move off to north.

2. Milankovitch Theory-

Change in Earth's orbit, rotation, and axial tilt affect solar radiation received on the Earth's surface and overall global temperatures. The time of these differing parameters seem to work well for explaining Pleistocene episodes of glaciation and interglaciation.

Proglacial Lakes-

Glacial lakes directly associated with the fronts of the glaciers

Glaciers advance during colder glacial periods

Glacial till, terminal moraines, and loess deposits

Neogene (Quaternary):

Holocene Epoch (Recent)- present to .01 mybp Pleistocene Epoch (Ice Age)- .01 to 1.8 mybp

Pluvial Lakes-

Lakes which form during cool climate times usually associated with glaciation, but not in direct contact with glaciers.

Rio-Grande Rift (New Mexico into West Texas)-

Rifting begins ~20 mybp, and has a duration of 10-12 my. (Starting in Late Oligocene into Early Miocene), a second phase of rifting starts in Mid-Miocene (17 mybp) and continues into Holocene. This rifting is accompanied by volcanism.

Quaternary Climate Details: Development of ice sheets and continental glaciers in...

both the northern and southern hemisphere during pleistocene

Quaternary Climate Details: Global cooling surge started at...

about 1.6 mybp

water weighs

approximately 8.34 pounds/gallon

Alpine Orogeny-

begins in Cretaceous but continues through Late Miocene - Alps, Atlas mountains and Pyrenees form.

-Solar output-

change in the suns output of energy

Ice age fauna

evolve and go extinct

Cooling in early Miocene triggers an....

expansion of the siliceous diatoms (SiO2 phytoplankton) in a belt northward from the Antarctic.

Marine Aquatic Environments: Invertebrates-

foraminifera, both benthic and planktonic, recover from major extinction at the end of the Eocene and undergo radiation in early Miocene.

Hominid Evolution-

occurred in the Plio-Pleistocene (Pliocene- Pleistocene) within the last two and a half million years for modern lineages of the genus Homo.

Glacial Lake Deposits -

often contain sediments and microfossils such as pollen for which a climate signal can be extracted.

Regions of the SW US contained large fresh water lakes during the Quaternary -

one large pluvial lake stood where the Great Salt Lake does today except in the past this was a fresh water lake

Glacial Isostacy occurs

over much of Canada and some parts of the US

US quaternary stratigraphy is determined by

sedimentary deposits and soils formed during periods of glacial advance and retreat in the mid-west.